1. Field of the Invention
The present invention relates to novel compounds having retinoid-like biological activity. More specifically, the present invention relates to 1-alkoxy and 1-acyloxycyclohex-1-enyl and aryl or 1-alkoxy and 1-acyloxycyclohex-1-enyl and heteroaryl substituted alkene derivatives and to their sulfur and 1-alkoxycarbonyl analogs having retinoid-like, retinoid antagonist or retinoid inverse agonist-like biological activity.
2. Background Art
Compounds which have retinoid-like activity are well known in the art, and are described in numerous United States and other patents and in scientific publications. It is generally known and accepted in the art that retinoid-like activity is useful for treating animals of the mammalian species, including humans, for curing or alleviating the symptoms and conditions of numerous diseases and conditions. In other words, it is generally accepted in the art that pharmaceutical compositions having a retinoid-like compound or compounds as the active ingredient are useful as regulators of cell proliferation and differentiation, and particularly as agents for treating skin-related diseases, including, actinic keratoses, arsenic keratoses, inflammatory and non-inflammatory acne, psoriasis, ichthyoses and other keratinization and hyperproliferative disorders of the skin, eczema, atopic dermatitis, Darriers disease, lichen planus, prevention and reversal of glucocorticoid damage (steroid atrophy), as a topical anti-microbial, as skin anti-pigmentation agents and to treat and reverse the effects of age and photo damage to the skin. Retinoid compounds are also useful for the prevention and treatment of cancerous and precancerous conditions, including, premalignant and malignant hyperproliferative diseases such as cancers of the breast, skin, prostate, cervix, uterus, colon, bladder, esophagus, stomach, lung, larynx, oral cavity, blood and lymphatic system, metaplasias, dysplasias, neoplasias, leukoplakias and papillomas of the mucous membranes and in the treatment of Kaposi's sarcoma. In addition, retinoid compounds can be used as agents to treat diseases of the eye, including, without limitation, proliferative vitreoretinopathy (PVR), retinal detachment, dry eye and other corneopathies, as well as in the treatment and prevention of various cardiovascular diseases, including, without limitation, diseases associated with lipid metabolism such as dyslipidemias, prevention of post-angioplasty restenosis and as an agent to increase the level of circulating tissue plasminogen activator (TPA). Other uses for retinoid compounds include the prevention and treatment of conditions and diseases associated with human papilloma virus (HPV), including warts and genital warts, various inflammatory diseases such as pulmonary fibrosis, ileitis, colitis and Krohn's disease, neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and stroke, improper pituitary function, including insufficient production of growth hormone, modulation of apoptosis, including both the induction of apoptosis and inhibition of T-Cell activated apoptosis, restoration of hair growth, including combination therapies with the present compounds and other agents such as Minoxidil.RTM., diseases associated with the immune system, including use of the present compounds as immunosuppressants and immunostimulants, modulation of organ transplant rejection and facilitation of wound healing, including modulation of chelosis.
Although pharmaceutical compositions containing retinoids have well established utility, retinoids also cause a number of undesired side effects at therapeutic dose levels, including headache, teratogenesis, mucocutaneous toxicity, musculoskeletal toxicity, dyslipidemias, skin irritation, headache and hepatotoxicity. These side effects limit the acceptability and utility of retinoids for treating disease.
It is now general knowledge in the art that two main types of retinoid receptors exist in mammals (and other organisms). The two main types or families of receptors are respectively designated the RARs and RXRs. Within each type there are subtypes; in the RAR family the subtypes are designated RAR.sub..alpha., RAR.sub..beta. and RAR.sub..gamma., in RXR the subtypes are: RXR.sub..alpha., RXR.sub..beta. and RXR.sub..gamma.. It has also been established in the art that the distribution of the two main retinoid receptor types, and of the several sub-types is not uniform in the various tissues and organs of mammalian organisms. Moreover, it is generally accepted in the art that many unwanted side effects of retinoids are mediated by one or more of the RAR receptor subtypes. Accordingly, among compounds having agonist-like activity at retinoid receptors, specificity or selectivity for one of the main types or families, and even specificity or selectivity for one or more subtypes within a family of receptors, is considered a desirable pharmacological property. Some compounds bind to one or more RAR receptor subtypes, but do not trigger the response which is triggered by agonists of the same receptors. A compound that binds to a biological receptor but does not trigger an agonist-like response is usually termed an antagonist. Accordingly, the "effect" of compounds on retinoid receptors may fall in the range of having no effect at all, (inactive compound, neither agonist nor antagonist) or the compound may elicit an agonist-like response on all receptor subtypes (pan-agonist). As still another alternative a compound may be a partial agonist and/or partial antagonist of certain receptor subtypes if the compound binds to but does not activate certain receptor subtype or subtypes but elicits an agonist-like response in other receptor subtype or subtypes. A pan-antagonist is a compound that binds to all known retinoid receptors but does not elicit an agonist-like response in any of the receptors.
Recently a two-state model for certain receptors, including the above-mentioned retinoid receptors, have emerged. In this model, an equilibrium is postulated to exist between inactive receptors and spontaneously active receptors which are capable of coupling with a G protein in the absence of a ligand (agonist). In this model, so-called "inverse agonists" shift the equilibrium toward inactive receptors, thus bringing about an overall inhibitory effect. Neutral antagonists do not effect the receptor equilibrium but are capable of competing for the receptors with both agonists (ligands) and with inverse agonists. U.S. Pat. No. 5,877,207 titled "Synthesis and Use of Retinoid Compounds Having Negative Hormone and/or Antagonist Activities" describes the foregoing two-state model and the use of retinoid antagonist and negative hormones in detail.
Inasmuch as naturally occurring retinoic acid includes a cyclohexene moiety, numerous patents and scientific publications which relate to the chemistry and biology of retinoids and related compounds are of interest as background to the present invention. Among the scientific publications Dawson and William H. Okamura, Chemistry and Biology of Synthetic Retinoids published by CRC Press Inc., 1990, pages 334-335, 354 and 324-356 is of special interest as an overview of the prior art on the subject. The publication Negishi, Ei-ichi, Anthony O. King, and William L. Klima, "Conversion of Methyl Ketones into Terminal Acetylenes and (E)-Trisubstituted Olefins of Terpenoid Origin", J. Org. Chem. 45 No. 12, 1980 p. 2526 is of interest as it relates to a process of synthesizing certain cyclohexene derivatives.
Among the numerous United States and foreign patents which disclose compounds having retinoid agonist, antagonist or inverse agonist like biological activity and are known to applicant, the following include a cyclohexane or cyclohexene ring structure and therefore are of interest as background to the present invention: U.S. Pat. Nos. 5,760,276; 5,618,836; 5,470,999; 5,451,605; 5,426,118; 4,539,154; 4,739,098; 4,923,884; 4,927,947 and EPO 0 272 921. U.S. Pat. No. 4,391,731; discloses certain cyclohexane derivatives suitable for use as liquid crystals.